US3590815A - Portable mechanical ventricular assistance device - Google Patents

Abstract

A portable mechanical ventricular assistance device including a ventricular assistor cup designed to receive the ventricles of the heart. The cup assembly is comprised of a rigid shell having a configuration generally conforming to the surface configuration of the heart ventricles and a flexible liner which is caused to contract and expand about the heart ventricles to effect the pumping action. The heart ventricles are retained within the cup by a substantially sustained negative pressure while the pumping action is produced by the application of alternating positive and negative pressure pulses to the cup. Both the sustained negative pressure and the positive and negative pressure pulses are generated by a hand pump assembly which includes a manually operable handle connected through a piston rod to a reciprocating piston mounted within the cylinder of the pump. The piston effectively divides the cylinder into two chambers, one of which is coupled through a conduit to provide the sustained negative pressure to the cup. The remaining chamber is coupled through a second conduit to the ventricle assistor cup to provide for the alternating positive and negative pressure pulses. Suitable adjustable relief valves are provided in each of the conduits to regulate the pressure levels and the positive or negative pressure directed to the cup.

Description

United States Patent Inventor Peter Schifl RD #2. Lambertville. NJ. 08530 Appl. No. 789,551 Filed Jan. 7, 1969 Patented July 6, I971 PORTABLE MECHANICAL VENTRICULAR Primary Examiner-L. W. Trapp Anomey0strolenk, Faber, Gerb & Soffen ABSTRACT: A portable mechanical ventricular assistance device including a ventricular assistor cup designed to receive the ventricles of the heart. The cup assembly is comprised of a rigid shell having a configuration generally conforming to the surface configuration of the heart ventricles and a flexible liner which is caused to contract and expand about the heart ventricles to effect the pumping action. The heart ventricles are retained within the cup by a substantially sustained negative pressure while the pumping action is produced by the application of alternating positive and negative pressure pulses to the cup. Both the sustained negative pressure and the positive and negative pressure pulses are generated by a hand pump assembly which includes a manually operable handle connected through a piston rod to a reciprocating piston mounted within the cylinder of the pump. The piston effectively divides the cylinder into two chambers, one of which is coupled through a conduit to provide the sustained negative pressure to the cup. The remaining chamber is coupled through a second conduit to the ventricle assistor cup to provide for the alternating positive and negative pressure pulses. Suitable adjustable relief valves are provided in each of the conduits to regulate the pressure levels and the positive or negative pressure directed to the cup.

PORTABLE MECHANICAL VENTRICULAR ASSISTANCE DEVICE The present invention relates to circulatory sustaining devices, and more particularly to a novel portable mechanical ventricular assistance device for sustaining the pumping action ofa heart.

Numerous devices have been developed to either sustain the circulatory function of a patient, or, alternatively, to sustain the pumping action ofa heart. All such devices may be classified into two basic categories; namely, bypass systems and indirect pumping systems. Devices falling into the category of bypass systems are designed to bypass the flow of blood from the heart and to maintain the pumping action otherwise performed by the heart through mechanical or electromechanical devices. Devices falling into the indirect pumping category are designed to assist the heart in the performance of its pumping function. The present invention falls into the latter category.

Devices classified in the former category are usually quite complex in nature and rather large in size so as to limit their use to operating rooms and effectively prohibit their use as a portable device.

Devices developed up to the present which are classified in the latter category are normally comprised of motor means for developing the necessary pressure or vacuum levels and are further comprised of electromechanical means for regulating the flow of the necessary pressure levels to the heart pump. Such equipment is likewise heavy in nature and large in size so as to prohibit its use as a truly portable device.

Devices of the indirect type have been used with great success in the fields of heart and organ transplants. When a potential cadaver (donor), whose organ or organs are available for transplant purposes, isto receive mechanical ventricular assitance, the assistor system is rushed to him for the purpose of sustaining the heart pumping action. Under presentday techniques and with present-day device, in order to transport the cadaver to the operating room, the assistor is temporarily disconnected, due to the fact that it is too bulky and requires too much electrical power to perform the circulatory function during the time in which the donor is being moved. The period during which the assistor device is disconnected may thus have a harmful effect upon the organ or organs to be transplanted.

The device of the present invention, which is designed to be truly portable and to be simple to connect and operate, is extremely advantageous for use during the period of time in which the donor is being moved from one location to another, as well as for other emergency situations.

The present invention is comprised of a ventricular assistor cup assembly having a rigid outer shell ofa configuration substantially conforming to the surface configuration of the heart ventricles. The cup contains a flexible liner capable of expanding and contracting about the heart ventricles to perform assistive pumping action.

The cup is provided with a first large opening for receiving the heart ventricles. A second opening provided at the apex of the cup receives the sustained negative pressure necessary to retain the ventricles within the cup assembly. A third opening provided in the cup along the surface thereof and intermediate the first and second openings is designed to receive the pulsatile pressures of alternating positive and negative pressure pulses which cause the contraction and expansion of the flexible liner about the heart ventricles.

All of the above-mentioned pressures are provided through the use of a single portable pump assembly having a first handle adapted to receive and position the operator's foot for holding the pump steady during operation. A second manually operable handle is provided for driving a reciprocating piston mounted within the pump cylinder. The piston effectively divides the pump cylinder into first and second chambers, each of which is coupled through an associated conduit to the sustained negative pressure opening and the pulsatile pressure opening, respectively. Adjustable relief valves are provided in the pulsatile pressure conduit to control the pressure (or vacuum) level of the pulse injected into the pulsatile pressure conduit. Similar adjustable relief vales are provided in the sustained negative pressure conduit for controlling the level of negative pressure and for bypassing positive pressure pulses from reaching the assistor cup assembly. An additional oneway valve assembly is provided in the sustained negative pressure conduit to prevent positive pressure pulses from reaching the assistor cup assembly and to maintain the negative pressure developed in the cup during the application of positive pressure pulses to the sustained negative pressure line.

The simplicity and portability of the system make it extremely advantageous for use in a variety of applications, especially those of an emergency nature. The portable system described herein may be easily and rapidly substituted for conventional assemblies in moving donors from one location to another, or may be used in emergency situations to sustain the circulatory function until such time as the patient is moved to a hospital.

It is, therefore, one object of the present invention to provide a nevel portable mechanical ventricular assistance device.

Still another object of the present invention is to provide a novel pump assembly for use with ventricular assistor cup assemblies, and the like, which is capable of developing a sustained pressure at a first output thereof and which is capable of developing a pulsatile pressure of alternating positive and negative pressure pulses at the second output thereof.

Yet a further object of the present invention is to provide a novel pump assembly for use with ventricular assistor cup assemblies, and the like, which is capable of developing a sustained pressure at a first output thereof and which is capable of developing a pulsatile pressure of alternating positive and negative pressure pulses at the second output thereof, whereby the pressure levels of the sustained and alternating pressure pulses are made adjustable through the use of adjustable valve means associated with each of the hand pump outputs.

These as well as other objects of the present invention will become apparent when reading the accompanying description and drawings in which:

FIG. 1 shows a diagrammatic view partially sectionalized of the pump assembly of the present invention as applied to a ventricular assistor cup assembly.

FIGS. 2a and 2b are schematic diagrams showing alternative embodiments for the pump portions of the assembly.

The device of the present invention is comprised of ahand pump assembly 10 for use in operating a ventricularassistor cup assembly 20.

The ventricular assistor cup assembly is described in greater detail in copending application (M-60l9) Ser. No. 785,652, filed Dec. 20, 1968 and assigned to the assignee of the present invention, which description is incorporated herein by reference thereto. For this reason, a detailed description of the assistor cup assembly will be omitted from this application for purposes of simplicity. For purposes of understanding the.

present invention it is sufficient to understand that theassistor cup assembly 20 is comprised of arigid cup 21 having a first large opening 22 for receiving the ventricles of the heart; asecond opening 23 arranged at the apex of the cup for receiving a sustained negative pressure line; and a third opening 24 for receiving a pulsatile pressure line. The interior of the cup is provided with aflexible liner 25 secured at 26 and 27 by suitable adhesive means, for example, near the apex opening 23 and the large opening 22, respectively. Theliner 25 is mounted within and sealed tocup 21 in such a manner as to form a hollow interior space whose only opening is opening 24 which receives the pulsatile pressure line. The injection of positive pressure into this hollow interior space causes the contraction ofliner 25 which, in turn, contracts the ventricles of the heart embraced by the liner. Injection of a negative pressure pulse returns theliner 25 substantially to the position shown in FIG. 1 to allow for expansion of the heart ventricles. This operation is continuously repeated to assist the heart in sustaining its pumping function. Theapex opening 23 receives the substantially sustained negative pressure to retain the ven tricles within the cup throughout the entire pumping operation and independently of the pulsatile pressure applied to opening 24.

The portable pump assembly for use with the ventricularassistor cup assembly 20 is comprised of acylinder 13 having secured at one exterior end thereof ahandle 12. The cylinder contains a reciprocating piston 14 of the double-acting piston type. Piston 14 is coupled through apiston rod 15 to an exterior mountedhandle 11. The opening provided forpiston rod 15 at the upper end ofcylinder 13 may be provided with a suitable seal such as an O-ring 16 to prevent the escape of compressed air from the cylinder.

Piston l4 effectively divides the cylinder into first andsecond piston chambers 17 and 18.

Upper chamber 17 is provided with anopening 18 for receiving a sustained negative pressure conduit 31 whichcouples chamber 17 through aliquid trap 32 andconduit 33 to the opening 23 provided in the apex ofassistor cup 21.

Lower chamber 18 is provided with anopening 34 for receiving aconduit 35 coupling the chamber to the pulsatile pressure opening 24 incup 21.

Suitable valve means are provided in the conduits connecting the assistor cup to the pump assembly for regulating the pressure level and pressure direction of pressure pulses in jected into each of the lines. The conduit 31 is provided with a first one-way valve assembly 36 which may, for example, be comprised of first and second spacedannular rings 37 and 38 arranged in the interior of conduit 31. A spherical member or ball 39 is normally urged against annular-shaped ring 38 by a bias spring 40 secured at one end toannular disc 37 and having its opposite end bearing against ball 39.

Similar one-way valve assemblies 41 and 46 are arranged at spaced intervals along conduit 31 to perform functions which will be more fully described.

In a like manner, positive and negativerelief valve assemblies 53 and 58 are arranged at spaced intervals along the surface ofconduit 35 for functions to be more fully described.

Theupper piston chamber 17 provides the sustained negative pressure for the ventricular assistor cup which is obtained on the down" stroke of piston 14. Let it be assumed that the piston 14 is positioned near the top ofcylinder 13 and is moved vertically downward in the direction shown by arrow A. A negative pressure or vacuum is developed inchamber 17. Due to the pressure differential across the right-hand and lefthand sides of one-way valve 36, ball 39 is caused to unseal the opening in ring 38, allowing this negative pressure (i.e., vacuum) state to communicate with theapex opening 23 incup 21.

Therelief valve assembly 46 is adjusted to causeball 49 to unseal the opening inring 50 when the negative pressure in conduit 31 is greater than a predetermined threshold level. Therelief valve 46 thus automatically controls the maximum negative pressure applied to the assistor cup. The maximum negative pressure may be made adjustable by providing suitable means for adjusting the bias applied toball 49 by bias spring 48. Asuitable filter member 51 is secured betweenring 50 and-ring 52 to filter out dust or any other unwanted particles carried by the air entering into the system whenvalve 46 opens.

The negative pressure applied to the assistor cup is sustained until the piston 14 reaches the bottom of its stroke. On the up' stroke, i.e., when the piston moves from the bottom of its stroke upward in the direction shown by arrow B, one-way valve 36 is sealed to prevent positive pressure from passing the valve and communicating with the assistor cup. The sealing of valve 36 during the entire "up" stroke also acts to maintain the negative pressure in assistor cup until the next down" stroke. One-way valve 41 releases the pressure being developed inupper chamber 17 during the upward stroke by having its ball 42 moved downwardly against the force of bias spring 43 to unseal the opening in annular-shaped ring 44. The negative pressure developed in conduit 31 during a down" stroke of piston 14 is thus sustained during theup" stroke of piston 14. Theliquid trap 32 traps any liquid passing fromcup assembly 20 toward the sustained negative conduit 31.

Lower piston chamber 18 operates in much the same manner asupper chamber 17 except that both positive and negative pulsatile pressures are applied to cup opening 24 byline 35. For this reason,conduit 35 is provided with two relief valves, one forpositive pressure 53 and one fornegative pressure 58.

During an up" stroke of piston 14, i.e., when piston 14 moves in the direction of arrow B, a negative pressure or vacuum is developed inconduit 35 and is coupled to cup opening 24, causing theflexible liner 25 to move from a contracted position to the relaxed position shown in dotted line fashion in FIG. 1. If this negative pressure exceeds a predetermined threshold level, theball 59 ofrelief valve 58 will move downward against the force of biasingspring 60 to unseal the opening in ring 61, thereby automatically controlling the maximum negative pressure which may be developed inconduit 35.

During a down" stroke of position 14, i.e., when the piston moves from its uppermost position downward in the direction shown by arrow A, a positive pressure is developed inlower piston chamber 18, causing a positive pressure pulse to be injected into opening 24 of the ventricular cup assembly. This causes theflexible liner 25 to contract the ventricles of the heart encircled by the liner. If the positive pressure injected intoconduit 35 exceeds a predetermined threshold level,ball 54 ofrelief valve 53 will be caused to move upwardly against the force of bias spring 55 to relieve the excess positive pressure developed inconduit 35. Therelief valves 53 and 58 thereby automatically control the positive and negative pressure pulses delivered tothei'ventricular cup assembly 20. Suitable adjustabie means may be provided in both the positive and negativerelief valve assemblies 53 and 58, respectively, to adjust the force of the biasing springs an thereby calibrate the maximum positive and negative pressure levels. The relief valves further limit the pressures as necessary for full strokes, regardless of the ventricular cup-pumping displacement. The negative relief valve assembly is provided with a filter 63 to filter out any unwanted particles or other material which may be in the atmosphere against entering into the system with the air entering through therelief valve assembly 58 whenever it is caused to open.

The pump may be operated by one person in a variety of ways. One preferred manner of operating the pump is to place one foot through the opening formed bystationary handle 12 and operating themovable handle 11 in a reciprocating fashion by grasping and movinghandle 11 with either one or both hands. Alternatively, each of thehandles 11 and 12 may be grasped by one hand, and the pump may be operated in a reciprocating fashion in this manner. Obviously, if desired, two persons may operate the pump, but the simplicity of operation and size of the pump does not necessitate such alternative operation.

FIGS. 2a and 2!) show alternative arrangements for the pump assembly of FIG. 1. Considering FIG. 2a, thepump arrangement 10! is a bellows pump selectively expandable and contractable due to itsbellows arrangement 70. The interior of the bellows arrangement is divided by abarrier wall 71 forming upper and lower chambers are coupled toconduits 31 and 35 of FIG. 1 in the same manner as the pump assembly shown in FIG. 1. Operation of the pump assembly of FIG. 2a may be performed in the same manner as the device shown in FIG. 1 by grasping thehandles 11 and 12 and urging them alternatively together and apart to create the positive and negative pressure phases occurring during each reciprocating cycle.

FlG.2b shows an alternative pump assembly having abellows assembly 70 comprised of a singleinternal chamber 72 havingopenings 73 and 74 for communicating with theconduits 31 and 35 of FIG. 1. In operation, the handles 1] and 12 are alternately urged toward one another and apart from one another to create positive and negative pressures within the internal chamber 72 to provide the positive and negative pressure signals inconduit 35 while providing only a sustained negative pressure signal in conduit 31.

When using the double-acting piston type of FIG. 1, it is possible to develop sustained negative pressure in conduit 31 during both the up" and down stroke by coupling an additional conduit near the bottom ofcylinder 13 which is provided with valve'assemblies substantially identical to theassemblies 36, 41 and 46. This additional conduit may be coupled into conduit 31 as shown by dotted line 31'. Thus, each stroke, whether up" or down, of the piston willcontribute to sustaining the negative pressure in the assistor cup assembly. This alternative embodiment may be used in cases where the pump assembly is capable of providing a sufficient negative pressure pulse for operating theflexible liner 25 and for simultaneously sustaining the negative pressure maintained at theopening 23 of the assistor cup assembly.

It can be seen from the foregoing description that the present invention provides a novel portable pump assembly especially advantageous for use with ventricular assistor cup assemblies to maintain and sustain the pumping operation of the heart by providing an independent sustained negative pressure (vacuum) at one output thereof and by providing alternating positive and negative'pressure pulses at a second output thereof for performing the functions necessary in the operation of such a ventricular cup assembly. It should be obvious that various modifications may be made in the pump assembly without departing from'the scope of the invention. For example, a one-way valve of the type shown in conduit 31 may be provided inconduit 35 for providing sustained negative pressures in each of the outputs developed by the pump for such applications in which negative pressures of this type might be required. The negative pressure values obtained may be adjusted to be of different values through simple adjustment of the valves. As a further modification, the one-way valves provided within each of theconduits 31 and 35 may be reversed in direction of operation so as to provide a first output for generating a positive sustained pressure and a second output for generating a sustained negative pressure. As still another alternative, the one-way valve assembly 36 provided in conduit 31 may be omitted to provide a pump having two outputs, each of which is capable of providing alternating positive and negative pressures wherein each of the positive and negative pressures developed by each of the outputs may be set at any predetermined threshold levels, depending upon the needs of the user. In addition, the single cylinder having a double-acting piston may be replaced by two cylinders each having a reciprocating piston. The cylinders may be placed side-by-side and arranged to be reciprocated by a single operating handle.

The assemblies of the figures may be operated by mechanical or electromechanical means, if desired. For example, a motor M may drive a reciprocating arm A through shaft S which is coupled to handle 11 of FIG. 1. A rotary to reciprocating motion device D converts the rotation of the shaft S into reciprocating movement. Alternatively, a relay R having a reciprocating armature RA may be alternately energized and deenergized to reciprocate up and down (for example) to impart reciprocating movement to the piston rod (for example). The down stroke may be imparted by energizing the relay driving its armature downward. Deenergization of relay R will cause the upstroke under control of a biassing spring (not shown).

Although this invention has been described with respect to particular embodiments, it should be understood that many variations and modifications will now be obvious to those skilled in the art, and, therefore, the scope of this invention is limited not by the specific disclosure herein, but only by the appended claims.

lclaim:

1. A portable mechanical ventricular assistance device comprising:

a ventricular assistor cup assembly including a rigid cup having an interior configuration adapted to receive the ventricles of the heart;

a flexible liner mounted within said cup having a first opening for receiving the ventricles of the heart; a first port positioned at the apex of the cup opposite the first opening, and a second port positioned intermediate the first opening and the first port;

said flexible liner being sealed to the interior surface of said cup along a first marginal portion adjacent to and surrounding said first opening and along a second marginal portion adjacent -to and surrounding said first opening and along a second marginal portion adjacent to and surrounding said first ports;

A first-sustained negative pressure conduit having a first end coupled to said first port;

a second pulsed positive and negative pressure line having a first end coupled to said second port;

reciprocating pump means having first and second outputs each capable of developing positive and negative pressure pulses during reciprocation of said pump;

said first and second outputs being respectively coupled to the second ends of said first and second conduits;

valve means coupled in said first conduit for coupling only negative pressure pulses to said first port.

2. The device of claim 1 further comprising first and second relief valve means connected to said second conduit for limiting the maximum positive and negative pressure pulses delivered to said second port.

3. The device of claim 1 further comprising first relief valve means coupled to said first conduit for limiting the negative pressure pulses delivered to said first port to a predetermined threshold level; and second one-way valve means for releasing positive pressure pulses injected into said first conduit to the atmosphere.

4. The device of claim 1 further comprising a liquid trap coupled between said first conduit and said first port for preventing the flow of any liquid toward said pump means.

5. The device of claim 1 wherein said pump means is comprised of a cylinder containing a reciprocally mounted doubleacting piston dividing said cylinder into first and second chambers;

said first and second outputs communicating respectively with said first and second chambers.

6. The device of claim 1 wherein said pump means is comprised of a cylinder having a collapsible bellows-type wall;

said first and second outputs communicating with the interior of said cylinder.

7. The device of claim 1 wherein said pump means is comprised of a cylinder having a collapsible bellows-type wall;

a barrier wall in said cylinder dividing said cylinder into first and second chambers;

said first and second outputs respectively communicating with the interiors of said first and second chambers.

Claims (7)

1. A portable mechanical ventricular assistance device comprising: a ventricular assistor cup assembly including a rigid cup having an interior configuration adapted to receive the ventricles of the heart; a flexible liner mounted within said cup having a first opening for receiving the ventricles of the heart; a first port positioned at the apex of the cup opposite the first opening, and a second port positioned intermediate the first opening and the first port; said flexible liner being sealed to the interior surface of said cup along a first marginal portion adjacent to and surrounding said first opening and along a second marginal portion adjacent to and surrounding said first opening and along a second marginal portion adjacent to and surrounding said first ports; A first-sustained negative pressure conduit having a first end coupled to said first port; a second pulsed positive and negative pressure line having a first end coupled to said second port; reciprocating pump means having first and second outputs each capable of developing positive and negative pressure pulses during reciprocation of said pump; said first and second outputs being respectively coupled to the second ends of said first and second conduits; valve means coupled in said firSt conduit for coupling only negative pressure pulses to said first port.

2. The device of claim 1 further comprising first and second relief valve means connected to said second conduit for limiting the maximum positive and negative pressure pulses delivered to said second port.

3. The device of claim 1 further comprising first relief valve means coupled to said first conduit for limiting the negative pressure pulses delivered to said first port to a predetermined threshold level; and second one-way valve means for releasing positive pressure pulses injected into said first conduit to the atmosphere.

4. The device of claim 1 further comprising a liquid trap coupled between said first conduit and said first port for preventing the flow of any liquid toward said pump means.

5. The device of claim 1 wherein said pump means is comprised of a cylinder containing a reciprocally mounted double-acting piston dividing said cylinder into first and second chambers; said first and second outputs communicating respectively with said first and second chambers.

6. The device of claim 1 wherein said pump means is comprised of a cylinder having a collapsible bellows-type wall; said first and second outputs communicating with the interior of said cylinder.

7. The device of claim 1 wherein said pump means is comprised of a cylinder having a collapsible bellows-type wall; a barrier wall in said cylinder dividing said cylinder into first and second chambers; said first and second outputs respectively communicating with the interiors of said first and second chambers.

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